Finally, the conditioning of anæsthesia by movements of the head, if
really proved, would rather corroborate this interpretation. For of
course the position of the head on the shoulders is as important for
localization of the retinal picture as the position of the eyes in the
head, so that sensations of head-movements must be equally represented
in the localization centers; and head movements would equally raise
the tension on those centers against discharge-currents from the
color-centers.

The conclusion from the foregoing experiments is that voluntary
movements of the eyes condition a momentary, visual, central
anæsthesia.

* * * * *




TACTUAL ILLUSIONS.

BY CHARLES H. RIEBER.


I.


Many profound researches have been published upon the subject of
optical illusions, but in the field of tactual illusions no equally
extensive and serious work has been accomplished. The reason for this
apparent neglect of the illusions of touch is obviously the fact that